Util.hs

module Util where

import           Data.Char   (toLower, toUpper)
import           Note        (Note (..))
import           Scale       (Scale, scalez)
import           System.Exit (ExitCode (..), exitWith)
import           Text.Read   (readMaybe)
import qualified Data.Map    as M


-- | Show all scales available.
listScalez :: IO ()
listScalez = mapM_ putStrLn $ M.keys scalez

-- | Transform a string into it's Note Representation.
strToNote :: String -> Maybe Note
strToNote s =
    case splitAt 1 s of
        (noteStr, "")  -> readMaybe $ map toUpper noteStr            :: Maybe Note
        (noteStr, "#") -> readMaybe $ map toUpper noteStr ++ "Sharp" :: Maybe Note
        _              -> Nothing

-- | Search the local scale-DB for a Scale.
strToScale :: String -> Maybe Scale
strToScale s = M.lookup (map toLower s) scalez

-- | CLI infos for user.
usage, complain, badArgs :: IO ()
usage    = putStrLn "scalez v 0.1\nUsage: scalez <rootnote> <scale> [--sing].\nList scales: scalez --list\n"
complain = putStrLn "Error: Faulty arguments.\n"
badArgs  = usage >> complain

-- | Give back meaningful status to OS.
exit, exitOhNo :: IO a
exit      = exitWith ExitSuccess
exitOhNo  = exitWith $ ExitFailure 1